lacasse@randvax.UUCP (Mark LaCasse) (06/12/86)
RE: Dialog in net.music.synth about how to absorb sound in a recording
or listening room by covering walls/ceilings/floors .....
Latest question raised: are plastic egg cartons flammable? (the real
ones eggs are sold in in the supermarket)
REPLY:
I am rather sure they are "flammable" in the building code sense. I think
you must be defining "flammable" as "bursts into flames when lit by a
match" or something. When a building starts to burn these things will be
exposed to thousands of degrees F. You bet they will burn then. What
kinds of toxic gases will they emit while burning?
For example, it is against building codes in most jurstictions to put
foil-faced fiberglass insulation rolls up on walls where the foil side
will be available to inhabitants. This is because the adheasive that
holds the foil unto the fiberglass is flammable. They rate these things
by flame spread rate when lit by high temperature flames. Experimenting
with it, I found the foil and its adheasive wouldn't sustain much of a
flame, even when lit with a propane torch. But it is still too flamable
for exposed wall surfaces (where fires are most likely to start). It is a
lot more flammable than wall-board/gypson-board! (BTW, there is a special
type of foil-backed fiberglass that is legal for exposure on walls,
FSK-25 (thats a flame spread rating). But it costs about 5 times as
much as the stuff they sell in the "building centers".
I read that even Sonex (original type) is too flamable to meet many building
codes for wall application. Sonex 2 might. A competitor to Sonex,
Soundcoat, claims their product is sufficiently fire proof to meet
building codes.
I read in a book in our local library, with a title something like
"How to build a small recording studio", that Owens Corning (or someone else)
makes a special fiberglass bat designed to absorb all audio frequencies
(except the very low end) equally. The author recommend using that in
wood framed boxes hung like big pictures on walls. The boxes were covered
with cloth, and about 4' x 4' x 3". Or he recommend using the same
audio-special fiberglass above a light weight drop-ceiling.
Does anyone know of better or cheaper ways to absorb sound (without
excessive fire risk)?
Mark LaCasse qantel!hplabs!sdcrdcf!randvax!lacasse
c/o The Rand Corporation cbosgd!ihnp4!sdcrdcf!randvax!lacasse
1700 Main Street lacasse@Rand-Unix
Santa Monica, CA 90406
213/393-0411 ext. 7420